@article{zhang2018comparison,
  title={On the comparison of gauge freedom handling in optimization-based visual-inertial state estimation},
  author={Zhang, Zichao and Gallego, Guillermo and Scaramuzza, Davide},
  journal={IEEE Robotics and Automation Letters},
  volume={3},
  number={3},
  pages={2710--2717},
  year={2018},
  publisher={IEEE}
}
